Like when something is so obvious but someone doesn’t get it…
For example, if someone won’t leave your home after dinner even after you drop hints like yawning, “wow it’s getting late” and “do you need a ride home” but they still won’t leave. In this scenario they are genuinely not understanding.
Not sure if I’m looking to describe the person or expectation of the information itself.
The opposite of having “common knowledge”.
Edit to add an example:
I went on a date with a guy from Spain (I’m in the US and never been to Spain). At one point he mentioned some sort of political policy back in Spain and I asked him some follow up questions since I didn’t know what he was talking about and was genuinely curious. He was ASTOUNDED I didn’t know every detail about Spain’s history and started reciting a series of dates going back hundreds of years and naming Spanish political figures and celebrities throughout history…I knew maybe 5% of them. It seemed like he was reciting the type of stuff a high school student would learn in history class. He kept saying it was all “common knowledge”. I explained that what he was saying was not regularly taught or common knowledge at least where I lived in the US. He still expected me to know everything and wouldn’t stop quizzing me…